This invention relates to lift chairs and, more particularly, to reclinable, elevator or lift chairs used by invalids, elderly, disabled and/or injured persons. In the care of such persons, there is commonly employed a chair having an occupant assisting feature in the form of a mechanical or electro-mechanical mechanism that powers the chair upwardly and forwardly to assist the occupant in moving from a sitting position to a standing position.
An example of a typical chair lift mechanism currently in use may be found in U.S. Pat. No. 5,165,753, issued Nov. 24, 1992 to Eldred D. Henderson, for an "Elevator Chair Apparatus" which is hereby incorporated by reference in its entirety. The '753 patent discloses a lift chair or elevator chair apparatus which is provided with a base portion having an inclined upper surface and a sub-frame assembly pivotally attached thereto along a forward edge. A mechanical ram powered by an electric motor pivots the sub-frame with respect to the base and about the forward pivot. The inclined upper surface of the base receives the sub-frame thereon in a fully downward position and defines the extreme reclined position. Pivotal rotation of the sub-frame with respect to the base and upon the pivot to an uppermost position defines the forward most lifting position. Throughout the moving process the chair remains rigid as the back is fixedly attached to the chair. Thus, the back of the chair is unable to attain a reclined position. Therefore, a need exists for a chair having improved flexibility in design whereby the occupant may achieve a fully reclined rest position.
Reclining chairs of the non-lifting type often allow for tilting of the back relative to the seat portion of the chair through the use of complex linking mechanisms. An example of one such chair of the motorized variety may be found in U.S. Pat. No. 4,365,836 issued to Jackson et al. on Dec. 28, 1982. The '836 patent discloses a seat which is coupled to a stationary frame by two quadrilateral linkages, one on each side of the chair. As known, the more complex the linking mechanism the more costly the chair. Therefore, a further need exists for a simplified and less costly linking mechanism for allowing the back to move relative to the seat in a reclinable chair.
As a result of these existing needs, it is an object of the present invention to provide a simplified and less costly motorized lifting chair of the type with a reclinable back.